ckchan wrote:
>
> Greetings,
>
> i really need some help here. been debuging for 2 days ! :O please tell
> me what's wrong with this short code. it's to make a LED blink. that's
> all. i tried the delay routine on PIC16F84, it's working. the LED blink
> ! but not with PICF874. The LED will ON permenantly. any configuration i
> missed out ? Thanks !

You have not initialised any other port except portD. Try setting all
the pins for the unused ports as outputs to get rid of the floating
inputs.

> %%        clrf    PORTD                   ; initialize port d
>        bsf     STATUS,RP0              ; select bank
>        movlw   B'00000000'             ; set port d as output pin
>        movwf   TRISD                   ;
> **        movlw   0H                      ; default low to port d
> **        movwf   PORTD                   ;
>        bcf     STATUS,RP0              ; de-select bank


The ** lines won't do as you expect because the RP0 bit is set, plus you
don't need them because of the %% line.

This delay routine is a bit shorter and uses less memory.

DELAY
        movlw msec_20
        movwf dvl
        clrf dv2   ; probably not needed
DLY1
        decfsz dv2
        goto DLY1
        decfsz dv1
        goto DLY1
        return

--
Best regards

Tony

http://www.picnpoke.com
mailto:sales@picnpoke.com